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Research on the structure of the Frobenius push-forwards on algebraic varieties and singularities in positive characteristic

Research Project

Project/Area Number 25400035
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Algebra
Research InstitutionTokyo University of Agriculture and Technology

Principal Investigator

Hara Nobuo  東京農工大学, 工学(系)研究科(研究院), 教授 (90298167)

Project Period (FY) 2013-04-01 – 2016-03-31
Project Status Completed (Fiscal Year 2015)
Budget Amount *help
¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2014: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2013: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Keywords代数幾何 / 正標数 / フロベニウス直像 / F爆発 / 大域的F有限型 / 大域的F正則 / 特異点 / ベクトル束 / 大域的有限F表現型 / フロベニウス写像
Outline of Final Research Achievements

We studied the Frobenius push-forwards on algebraic varieties and their singularities in positive characteristic p, focusing on a few classes of projective varieties and normal surface singularities. Our results are as follows.
1. We classified the structure of the F-blowup sequence of a simple elliptic singularity in terms of the characteristic p, the self-intersection number of the exceptional elliptic curve E on the minimal resolution, and whether E is ordinary or supersingular.
2. We studied the Frobenius push-forward of the structure sheaf of the surface obtained by blowing up the projective plane at n points in general position. In case n=4 (del Pezzo surface of degree 5), we determined all the indecomposable direct summands of the iterated Frobenius push-forwards, and proved that their isomorphism classes are finite (GFFRT). We also proved that these Frobenius summands generate the derived category in case n=4. In case n=10, we constructed a rational surface that is not GFFRT.

Report

(4 results)
  • 2015 Annual Research Report   Final Research Report ( PDF )
  • 2014 Research-status Report
  • 2013 Research-status Report
  • Research Products

    (10 results)

All 2016 2015 2014 2013 Other

All Journal Article (3 results) (of which Peer Reviewed: 3 results,  Acknowledgement Compliant: 2 results) Presentation (7 results) (of which Int'l Joint Research: 1 results,  Invited: 6 results)

  • [Journal Article] Looking out for Frobenius summands on a blown-up surface of P^22015

    • Author(s)
      N. Hara
    • Journal Title

      Illinois J. Math.

      Volume: 59 Pages: 115-142

    • Related Report
      2015 Annual Research Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Structure of the F-blowups of simple elliptic singularities2015

    • Author(s)
      N. Hara
    • Journal Title

      J. Math. Sci. Univ. Tokyo

      Volume: 22 Pages: 193-218

    • NAID

      120006906130

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] F-blowups of normal surface singularities2013

    • Author(s)
      N. Hara, T. Sawada, T. Yasuda
    • Journal Title

      Algebra Number Theory

      Volume: 7 Issue: 3 Pages: 733-763

    • DOI

      10.2140/ant.2013.7.733

    • Related Report
      2013 Research-status Report
    • Peer Reviewed
  • [Presentation] A few remarks on Frobenius summands on rational surfaces2016

    • Author(s)
      Nobuo Hara
    • Organizer
      Younger Generation in Algebraic Geometry and Complex Geometry
    • Place of Presentation
      National Taiwan University,台北市(中華民国)
    • Year and Date
      2016-01-14
    • Related Report
      2015 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] A few remarks on Frobenius summands on rational surfaces2015

    • Author(s)
      原 伸生
    • Organizer
      RIMS研究集会「特異点と不変量」
    • Place of Presentation
      京都大学数理解析研究所(京都市)
    • Year and Date
      2015-12-15
    • Related Report
      2015 Annual Research Report
    • Invited
  • [Presentation] Looking out for Frobenius summands on certain rational surfaces2014

    • Author(s)
      原伸生
    • Organizer
      正標数セミナー
    • Place of Presentation
      東大数理
    • Year and Date
      2014-11-17
    • Related Report
      2014 Research-status Report
  • [Presentation] Looking out for Frobenius summands on certain rational surfaces2014

    • Author(s)
      原伸生
    • Organizer
      研究集会「代数多様体とその周辺」
    • Place of Presentation
      琉球大学
    • Year and Date
      2014-09-29
    • Related Report
      2014 Research-status Report
    • Invited
  • [Presentation] Stabilization of Frobenius push-forward and the F-blowup sequence

    • Author(s)
      Nobuo Hara
    • Organizer
      The Commutative Algebra of Singularities in Birational Geometry
    • Place of Presentation
      Mathematical Sciences Research Institute, Berkeley, USA
    • Related Report
      2013 Research-status Report
    • Invited
  • [Presentation] Stabilization of Frobenius push-forward and F-blowup sequence

    • Author(s)
      原伸生
    • Organizer
      代数幾何学城崎シンポジウム
    • Place of Presentation
      兵庫県立城崎大会議館
    • Related Report
      2013 Research-status Report
    • Invited
  • [Presentation] The iterated Frobenius push-forward on rational surfaces

    • Author(s)
      Nobuo Hara
    • Organizer
      Birational Geometry and Singularities in Positive Characteristic
    • Place of Presentation
      東京大学
    • Related Report
      2013 Research-status Report
    • Invited

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Published: 2014-07-25   Modified: 2019-07-29  

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